The present invention relates to a method and apparatus for controlling an internal combustion engine.
It is known in the art to store an array of engine control variables in a map of a microcomputer and address an appropriate one in response to a set of corresponding engine operating parameters. The control variable derived from the map is used to control one of a plurality of engine input variables such as air-fuel mixture, ignition timing and so on. An engine control apparatus, as shown and described in Japanese Patent Publication (Tokkaisho) No. 56-96132, comprises a pair of such engine control maps in which different set of control variables are stored. These maps are selectively addressed according to different engine operations so that in response to a transient condition the control variables are switched from one map to another with or without hysteresis. Due to the switching action, there occurs a rapid change in engine control which is likely to result in unpleasantness in driving and a deviation in air-fuel ratio from a controlled point.